Difference between revisions of "Equilateral triangle"
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(Equilateral means equal-length sides, not equal angles. It happens that equilateral triangles ARE equiangular, but this is not true for polygons of more than three sides.) |
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| − | An equilateral triangle has equal | + | An equilateral triangle has, by definition, three sides that are equal in length. |
| + | It can easily be proved that an equilateral triangle is also ''equiangular,'' that is each of its three angles is equal; since another theorem states that the three angles of a triangle total 180°, each of its angle is 60° each. | ||
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| + | Note that it is only ''triangles'' that have the characteristic that equilateral means equiangular. For polygons of more than three sides, this is not true. A quadrilateral can have four equal sides—be a [[rhombus]]—without necessarily being a square. | ||
[[Image:Triangle.Equilateral.svg]] | [[Image:Triangle.Equilateral.svg]] | ||
[[category:geometry]] | [[category:geometry]] | ||
Revision as of 17:08, April 3, 2007
An equilateral triangle has, by definition, three sides that are equal in length.
It can easily be proved that an equilateral triangle is also equiangular, that is each of its three angles is equal; since another theorem states that the three angles of a triangle total 180°, each of its angle is 60° each.
Note that it is only triangles that have the characteristic that equilateral means equiangular. For polygons of more than three sides, this is not true. A quadrilateral can have four equal sides—be a rhombus—without necessarily being a square.
